One essential step in the milking process for dairy animals, such as cattle, goats, sheep, horses, buffaloes and the like, is to effectively clean the teats of the animal to be milked before the actual milking can start. If the teats are not properly clean then the milk is likely to become contaminated by dirt on the teats and will not be fit for human consumption. If milk from one animal, whose milk happens to be contaminated, is collected in a large receptacle together with milk from other animals, large quantities of milk may have to be discarded. Furthermore the whole milking system will have to be thoroughly cleaned before a new animal can be milked. Consequently, failure to clean the teats properly will be both costly and time-consuming. Therefore the cleaning is an essential operation which should take place before the actual milking can be performed.
To obtain proper cleaning is especially difficult if an automatic milking system is used, since there is no checking performed by a person as is the case during manual cleaning. It is particularly important that the tips of the teats are cleaned as any contamination present here will naturally be picked up by the flow of milk and carried into the milk reservoir.
One of the most frequent ways of cleaning teats and udders is using one or several brushes or similar equipment which perform cleaning by means of friction, which is the result of moving the brushes against the teats/udder. This may be performed as a dry cleaning or as wet cleaning process. In the case of dry cleaning no liquid is added, and in wet cleaning a liquid, such as water and a detergent, is added, which is considered to improve the cleaning process.
FR-A-2 559 351 shows a teat-cleaning device comprising a hand unit which contains two horizontal parallel cylindrical brushes which are separated by a gap which is large enough to permit a teat to pass between the brushes. The brushes counter rotate so that in the gap the bristles of the brushes move downwards and brush contamination downwards towards the tip of the teat. When the teat is withdrawn from the device it is hoped that the tip will be brushed clean but no special provisions are made to brush the tip of the teat.
A device shown in EP-B 0 399 132 comprises a teat-cleaning device comprising a hand unit which also contains two horizontal parallel counter-rotating cylindrical brushes and additionally a tip cleaning third brush mounted below the first two brushes. As the teat is introduced into the hand unit a horizontal guide roller below the first brushes is intended to guide the tip of the teat into contact with the third brush. In order to achieve satisfactory brushing of the tip of a teat with a brush made of bristles it is important that the tips of the bristles come into contact with the area to be cleaned. This causes contaminants to be flicked off the tip of the teat. If, on the contrary, the tip of teat is introduced too far into the third brush such that the tip comes into contact with the bristles near their roots then the bristles tend to bend back which cause contamination to be smeared around the tip instead of being flicked away. As the three brushes are fixed in relation to each other teats which are too short to reach the third roller do not have their tips cleaned and tips which are too long may be subjected to smearing of contaminants or are otherwise inadequately cleaned.